Sleep issues are just another thing for people suffering from cancer to add to the range of complications that this condition throws at them.
Frequently visiting the doctor, pain, various side effects, and other issues may be challenging to deal with. However, sleep issues are there all the time at the end of every day, and can make the other symptoms of cancer worse.
Frequently failing to get a good sleep can make pain feel sharper and the emotional stress of cancer harder to deal with. Being tired makes coping with the disease much more difficult, let alone the effects that poor sleep has on living with cancer. Evidence suggests that sleep problems can increase the risk of contracting cancer.
It is important to understand how lack of sleep and cancer are linked to be able to reduce the risk of it developing. It will also allow people to learn how to deal better with sleep problems during cancer treatment. This article will cover how cancer and sleep are linked, the sleep issues that are linked to cancer, and how best to deal with sleep problems for those suffering from cancer.
Table of Contents
How cancer linked to lack of sleep
Good sleep is generally regarded as essential for good health and wellbeing, but as yet there is no categorical evidence linking cancer to lack of sleep. Having said that, there is a considerable amount of research suggesting that there may be a link.
The sleep problem associated with cancer is generally one of the following:
- Chronic sleep deprivation
- Sleep apnea
- Shift work sleep disorder.
Chronic sleep deprivation
This generally refers to occasions when a person has not had sufficient sleep. However, this is a subjective term as 7 hours sleep a night are recommended, but more or less than this may be sufficient or needed depending on the person.
Someone may feel deprived of sleep after only one night. However, chronic sleep deprivation is a sustained lack of sleep and can often develop into insomnia. In these cases a person will regularly experience difficulties falling and staying asleep.
Sleep deprivation can even occur when someone has slept all night, but the sleep has been restless. This is often the case with shift work sleep problems or sleep apnea which we will cover shortly.
Having chronic sleep deprivation will impair a person's cognitive abilities, worsen their judgement, and reduce their ability to moderate their mood and emotions. It will weaken their immune system which could result in them gaining weight. This goes some way to explain why sleep issues are associated with diabetes, obesity, and other health problems.
Many of these health problems that derive from lack of sleep are risk factors for cancer. Obesity, for instance, is widely accepted as being a risk. However, growing evidence suggests that sleep problems themselves could be a risk for several types of cancer including:
- Prostate cancer. A 2013 study of 2,100 men over 3-7 years concluded that men with insomnia were almost twice as likely to develop prostate cancer within the same timescale. It also indicated that more severe sleep disorders resulted in more severe cancer.
- Breast cancer. A study of about 24,000 women in 2008 discovered that having one less hour of sleep (6 rather than 7) produced a 1.62-fold likelihood of developing breast cancer. Similarly to the severity pattern found in prostate cancer, a 2012 study indicated that more severe sleep problems produced more severe breast cancer.
- Colon cancer. Just one hour less of sleep seems to have a significant effect on the development of cancer. One study put the likelihood as 50% above average for cancer of the colon.
This is s potentially life-threatening condition as the person will stop breathing during sleep. This can result in choking, gasping for breath, or heavy snoring, which forces the brain to wake up for a short period to restart the breathing process.
A person with sleep apnea will very often be awoken by their condition. However, even if they are not consciously awoken, the disruption they experience will still disrupt the quality of their sleep.
Good quality of sleep is considered to be 7 hours of uninterrupted sleep. During this time a person will go through the various stages of the sleep cycle - from light sleep to rapid eye movement (REM) sleep. Each stage of the sleep cycle happens for different reasons. Muscles and tissues get repaired during deep sleep, the mind undergoes repair during REM sleep.
The majority of REM sleep occurs during the latter part of the cycle and if the cycle gets interrupted by sleep apnea, it will start all over again. The result is less REM sleep which causes the cognitive and emotional deltas of sleep deprivation, making it more challenging to maintain a positive mental attitude. A positive attitude may be linked to increased rates of cancer survival, or it may not. It is certain that sleep apnea makes managing the symptoms of cancer much more difficult.
Sleep apnea can happen if a person's airway gets blocked. This can occur as a result of obesity when the airway is blocked by fatty tissues around the throat. It can also occur through a communication failure between the brain and the muscles that control breathing.
We are certain that sleep apnea is linked to cardiovascular diseases, diabetes, and obesity. Recent research indicates that it may also be associated with cancer:
- Head and neck cancer: One study concluded that 80% of people with cancer of the head and neck also suffer from sleep apnea and are more prone to postoperative complications.
- Severity of cancer: A study of around 5,000 people discovered a correlation between the severity of sleep apnea and the onset of cancer. Men under the age of 65 were identified as being particularly at risk.
- Cancer morbidity: Data from one study were used to categorize patients based on the severity of their sleep apnea. Those with extreme sleep apnea were 5 times more likely to die from cancer.
An explanation for why sleep apnea and cancer are linked might be found in a 2014 study of mice. Tumor-infected mice were split into 2 groups. One group was subjected to restrictions of oxygen to replicate the effects of sleep apnea. The results showed that the group subjected to restricted oxygen had faster growth of tumors than the control group.
When the body is denied oxygen, it reacts by producing more blood vessels. This boosts the growth of cancerous tissues.
Shift work sleep disorder
This condition affects the circadian rhythm of individuals who work nonstandard work patterns, such as nights or shifts.
Circadian rhythms are the body's natural patterns - when one feels hungry, tired, or energetic. The human circadian rhythms align with the pattern of the sun - the literal translation of circadian is ”around the day”.
Shift work patterns are often contrary to circadian rhythms. This can cause someone who works shifts to be in a continuous state of sleep deprivation. It is like a form of jetlag.
Of course, this will result in them experiencing the symptoms of sleep deprivation, so they are more likely to become moody, suffer poor judgement, or lose cognitive ability.
Shift work sleep disorder has been linked to being a risk factor for several types of cancers:
- Prostate cancer: various studies have observed shift work as increasing the risk of prostate cancer.
- Breast cancer: women who work shifts run a higher risk of breast cancer.
- Colorectal cancer: a study conducted in 2003 on nurses working night shifts found that nurses who worked night shifts for 15 or more years for as little as 3 days per month were much more prone to contracting colorectal cancer. Such studies suggest that the risk of cancer may increase depending on the length of time spent working shifts during career.
Disrupting the circadian rhythms in the way that shift work does affects not just a person's sleep. Circadian rhythms also play a part in a person's routine biological functions such as the production of hormones, functioning of the organs, etc.
An abnormal circadian rhythm could jeopardize these functions by making them more vulnerable during normal work patterns.
One biological function that may explain the relationship between poor sleep in shift work and cancer particularly well is the production of hormones. The hormone that regulates your sleep is called melatonin. The brain triggers production of melatonin when sunlight starts to diminish, indicating the onset of nighttime. As shift workers generally experience less sunlight and more artificial light, their production of melatonin suffers.
As with all biological functions, the production of melatonin does not happen in isolation. As it decreases, the production of estrogen increases. As this hormone increases, so does the risk of breast cancer. This was hypothesized by researchers during a 2003 study into melatonin levels and breast cancer.
A hormone that acts inversely to melatonin is cortisol - its levels rise in the morning and fall after dark. Studies into shift work found that people adopting these work patterns typically had higher levels of cortisol.
Sleep problems linked to cancer
Cancer diagnosis is not the end of the line for sleep problems. Unfortunately in most cases they get worse. Cancer symptoms and treatment are wide ranging and disrupt all aspects of daily life. Sleep is no exception. Cancer treatment may bring about new sleep problems or make existing ones worse.
People may experience pain and discomfort during treatment, which makes relaxing and sleeping more difficult. It may also affect a person's temperature, bringing on night sweats which again prohibit decent sleep. Cancer can strongly lead to depression, stress, and anxiety, all of which make sleeping more of a challenge and can lead to insomnia.
Statistically, around 70% of women with breast cancer and about half of men with prostate cancer have sleep problems. Regardless of the type of cancer approximately 30-75% of cancer patients have problems with sleeping.
Cancer treatment, chemotherapy drugs, and other medications can cause fatigue and excessive daytime tiredness. The feelings of extreme tiredness and sleepiness make people sluggish and inactive through the day. People can even experience this following an apparently good night's sleep.
Many medications for decreasing nausea for cancer patients have extreme drowsiness as a side effect. Excessive daytime sleepiness differs from fatigue in that fatigue describes a state of low energy and a need for relaxation, whereas excessive daytime sleepiness creates the desire to sleep. Cancer patients experiencing either of these two conditions may be prone to snoozing during the day, which will make sleeping at night harder.
Insomnia is a condition whereby a person has difficulty both falling and staying asleep. Insomnia is three times more likely in cancer patients than in the rest of the population.
The stress and anxiety that generally comes hand in hand with cancer can bring on or aggravate insomnia. Add the sleep disrupting side effects of many cancer medications such as steroids which are particularly energizing, and the resulting insomnia can cause cancer patients to get into a spiraling cycle of fatigue and daytime exhaustion.
Restless legs syndrome (RLS)
RLS occurs when a person is lying down. It is a sensation of extremely uncomfortable tingling in the lower limbs and movement is the only way to relieve it. The need to be constantly moving makes falling and staying asleep very difficult.
RLS appears to exist alongside certain cancers. Women suffering breast cancer and older prostate cancer patients have twice the likelihood of getting RLS. One study found that one in five people undergoing chemotherapy had RLS; twice the risk as against the general population.
Tips for better sleep for cancer patients
Life is easier after a good night's sleep. A good night's sleep helps cancer patients stay strong and battle the disease.
Therapies for better sleep
Cognitive behavioral therapy for insomnia (CBT-I) is one of the most effective ways to treat many of the sleep conditions experienced by cancer sufferers. Patients work with a CBT-I therapist over several sessions of sleep techniques and practices which include:
- Reframing: patients work on reviewing their negative feelings, thoughts, and emotions related to sleep, and developing positive and more mindful habits.
- Relaxation techniques concentrate on muscle relaxation and deep breathing exercises to physically relax the body into a sleep-conducive state. By completing these exercises the mind has something other to focus on than agonizing about cancer.
- Sleep hygiene: patients learn good sleep habits - to follow a good bedtime routine, adhere to a set sleep schedule, maintain the bedroom in a good state, and avoid heavy eating, caffeine, or alcohol before going to sleep.
Sleep restriction therapy can be practiced alongside CBT-I. People work with their therapist to develop a suitable sleep schedule - what time they go to bed and what time they should wake up.
Once the schedule is agreed, it has to be strictly followed. The only time they are permitted to be in bed or the bedroom is during the agreed sleeping times. They have to leave the bedroom at the agreed waking times regardless of whether they had the full 7 hours of sleep or not. Napping during the day is strongly discouraged. The theory is that the brain is forced to accept this new sleeping habit by restricting its ability to sleep.
Light therapy is a technique that uses lamps and light boxes which have the same relative brightness as the sun. People with sleep disorders sit in front of the light from 15 minutes to an hour at a time in order to reset their circadian rhythms. Shift workers in particular can benefit from light therapy.
Continuous Positive Air Pressure (CPAP) therapy has been found to be very effective in treating people with extreme sleep apnea. Patients sleep with a CPAP mask over their faces whilst sleeping. Consistent air pressure is applied to the face, maintaining an open airway while they sleep, thus preventing sleep apnea from occurring.
Products designed to help cancer patients sleep
Cooling mattresses can provide relief for cancer patients by reducing night sweats or hot flushes. These mattresses are designed to be breathable and use materials such as latex or gel-infused foams, which gives a cooler sleeping surface.
White noise machines can assist people with insomnia to fall asleep. There are electronic devices or smart phone applications with extensive libraries of natural sounds, classical music, or white noise designed to block out noise distractions and thoughts that keep them awake.
Weighted blankets can have a very relaxing effect on many people, particularly those with RLS. These blankets are generally fitted to around 10% of the person’s weight plus one pound. So if a person weighs 150lbs, s/he will need a blanket weighing 16 pounds (15+1).
You can access a variety of other resources for help and advice on sleep problems and cancer. Here are just a few:
The American Cancer Society is a nonprofit organization leading the way in raising awareness of cancer, funding research into cures for it, and fighting it. The website offers plenty of resources for patients, survivors, and caregivers. It offers a 24-hour Live Chat and toll-free helpline at 1-800-227-2345.
The National Cancer Institute provides learning resources and publishes the results of the latest government-funded research into cancer.
Patients, survivors, and caregivers can get support via online forums such as: